Dear All, I must be stuck on something pretty basic (I am struggling badly with I/O). Let us assume you have a rather simple file mydata.dat (3 columns of integer numbers), see below. 1246191122 1336 1337 1246191142 1336 1337 1246191162 1336 1337 1246191182 1336 1337 1246191202 1336 1337 1246191222 1336 1337 1246191242 1336 1337 1246191262 1336 1337 1246191282 1336 1337 1246191302 1336 1337 1246191322 1336 1337 1246191342 1336 1337 1246191362 1336 1337 1246191382 1336 1337 1246191402 1336 1337 1246191422 1336 1337 Now, my intended pipeline could be read file as string--> convert to list of integers-->pass it to hmatrix (or try to convert it into a matrix/array). Leaving aside the last step, I can easily do something like let dat=readFile "mydata.dat" in the interactive shell and get a string, but I am having problems in converting this to a list or anything more manageable (where every entry is an integer number i.e. something which can be summed, subtracted etc...). Ideally even a list where every entry is a row (a list in itself) would do. I found online this suggestion http://bit.ly/9jv1WG but I am not sure if it really applies to this case. Many thanks Lorenzo